This invention relates to a fuel control system for internal combuston engines and more particularly to an improved cold starting and warm up fuel control for such engines.
As is well known, it is desirable, if not necessary, to provide additional fuel to an internal combustion engine to assist in its cold starting. In addition to providing additional fuel for cold starting, additional fuel should also be provided when the engine is cold during its warm up operation. The amount of fuel required for warm up is, however, less than that necessary for starting. Various devices have been proposed for achieving cold starting and cold running enrichment. One type of device normally employed for this purpose is a choke valve which is disposed in the intake system of the engine carburetor and which may be operated to provide cold starting and cold running enrichment. The use of choke valves, however, have a number of disadvantages. The choke valve per se does not always provide the desired degree of enrichment for all starting and running conditions. The provision of a choke valve in the induction system also causes a restriction to the flow, at times when choke operation is not necessary. Therefore, the use of the choke valve, even though it is fully opened, may restrict the maximum power output of the engine. Furthermore, if multiple carburetors are employed, it is necessary to provide some interlinking between the choke valves of the various carburetors so that they will all be operated in unison.
Another form of cold starting and cold running enrichment device is the provision of a separate starter system that provides additional fuel during cold starting and/or cold running. Such starter systems also are not fully satisfactory because they are incapable of providing both the necessary degree of enrichment for starting and a proper running mixture during cold warm up. In addition, where multiple carburetors are employed, it is also desirable to interlink the starting systems associated with each carburetor which, as aforenoted, can cause undue complication.
It is, therefore, a principal object of this invention to provide an improved device for cold starting and cold running.
It is a further object of the invention to provide an improved enrichment device for cold operation that will provide stable engine speed during the warm up cycle.
It is a further object of this invention to provide an improved and simplified cold starting and cold running enrichment device for multiple cylinder engines.